Why does the disease occur?
The dystrophin gene is located on the X chromosome. In boys there is only one, so a breakdown of the gene immediately leads to a lack of protein and disease. In girls, a second healthy X chromosome usually compensates for the defect, and they remain carriers, although some have mild weakness or heart changes. In about a third of patients, the mutation occurs for the first time, and there is no previous history of cases in the family. Dystrophin serves as a kind of shock absorber for the muscle cell membrane; without it, the fibers break during exercise, and the enzyme creatine kinase is released into the blood.
- X-linked recessive mode of inheritance
- Mostly boys are affected
- Mothers are most often carriers
- Some mutations occur for the first time
- A milder version of the same gene is Becker muscular dystrophy
Early signs
The reason for contacting is usually that the child lags behind his peers in physical activity. He later begins to walk, runs awkwardly, cannot jump on one leg, gets tired quickly, and asks to be held. A characteristic sign is the Govers maneuver: to get up from the floor, the child turns over on his stomach and rises, moving his hands to his hips. The calf muscles look enlarged and dense, but this “muscularity” is deceptive: muscle tissue is replaced by fat. Some children have speech delays and learning difficulties.
- Delay in onset of independent walking
- Frequent falls and fatigue
- Getting up from the floor using the Govers maneuver
- Walking on toes, waddle gait
- Enlarged calf muscles
- Sometimes - delayed speech development
How to make a diagnosis
The first step is extremely simple and accessible: a blood test for creatine kinase. With this disease, its level is increased tenfold, and such a result in a boy with muscle weakness almost always means muscular dystrophy. The diagnosis is confirmed by a genetic study of the dystrophin gene, which reveals the type of mutation - this is important both for the family and for the choice of therapy. Muscle biopsies are performed less frequently today, only when genetic testing is inconclusive. Additionally, the state of the heart and breathing is assessed, as they are involved in the process.
- Blood creatine kinase
- Genetic study of the dystrophin gene
- ENMG with an unclear picture
- Muscle biopsy in selected cases
- ECG and echocardiography
- Respiratory function assessment
- Examination of mother and sisters for carrier status
Treatment and support
There is no curative therapy yet, but treatment with glucocorticoids in special regimens has been proven to slow the loss of muscle strength and prolong the ability to walk independently for years. It is prescribed and monitored by a neurologist, since the drugs have side effects that require monitoring. Rehabilitation is of great importance: stretching to prevent contractures, orthoses, breathing exercises, properly selected physical activity without overload. Regular monitoring by a cardiologist is mandatory, because the heart muscle suffers in the same way as the skeletal muscle. Genetic treatments are developed and applied for individual mutations.
- Glucocorticoids according to the regimen prescribed by a neurologist
- Regular stretching and contracture prevention
- Orthoses and technical means of rehabilitation
- Breathing exercises and control of lung function
- Observation by a cardiologist with echocardiography
- Controlling weight, vitamin D and bone density
- Vaccination against respiratory infections according to the calendar
Family and planning
After confirming the diagnosis, it is important to examine the patient’s mother and sisters for carrier status: this affects both pregnancy planning and their own health, since carriers experience changes in the heart muscle. The geneticist will explain the risks for future children and the possibilities of prenatal diagnosis. The child needs not only medical, but also social support: learning in a comfortable environment, psychological assistance to the family, communication with other families. Early planning for technical equipment and housing adaptations will make life much easier in the future.
- Examination of mother and sisters for carrier status
- Consultation with a geneticist when planning pregnancy
- Observation by a cardiologist in carriers
- Psychological support for family
- Adaptation of housing and school
- Planning technical means of rehabilitation
- Leading a team of specialists